7th Grade Honors Life Science - Cell Structures and Processes

Vocabulary flashcards covering cell theory, prokaryotic and eukaryotic types, organelles, metabolic processes like photosynthesis and respiration, membrane transport, and cell division.

Cell

The smallest unit that is capable of performing life functions.

Cell Theory

The scientific theory stating that all organisms are composed of one or more cells, all cells arise from pre-existing cells, and the cell is the structural and functional unit of all living things.

Prokaryotic Cells

Simple cells that do not have a nucleus or structures surrounded by membranes, such as bacteria.

Eukaryotic Cells

Complex cells that contain a nucleus and organelles surrounded by membranes, found in plants, animals, fungi, and protists.

Organelles

Known as 'little organs,' these are the little parts that make up the cell.

Cell Nucleus

The 'control center' of the cell that controls activity and houses the genetic material (DNA).

Cytoplasm

A jelly-like fluid material between the cell membrane and the nucleus that protects and stores cell components and gives the cell its shape.

Cell Membrane

A flexible barrier found on all types of cells that controls what enters and leaves the cell through selective permeability.

Cell Wall

A structure that forms a flexible barrier around the cell to provide support and protection.

Chloroplasts

Organelles found in plants and algae that contain chlorophyll and capture energy from the sun to make food via photosynthesis.

Lysosomes

Spherical organelles containing digestive enzymes that digest and recycle used cell components or invaders; known as the 'waste dumps' of the cell.

Mitochondria

Known as the 'powerhouse of the cell,' these double-membrane organelles release energy from food to produce $ATP$ during cellular respiration.

Chemical Energy

Energy stored in the bonds between the atoms of every molecule.

Photosynthesis

The process occurring in chloroplasts where plant cells take in light energy and change it into chemical energy: $Sunlight + H_2O + CO_2 \rightarrow C_6H_{12}O_6 + O_2$.

Cellular Respiration

The process of breaking down food to release chemical energy: $C_6H_{12}O_6 + O_2 \rightarrow CO_2 + H_2O + ATP$.

Selective Permeability

The quality of the cell membrane that allows it to let some materials pass through while others cannot.

Passive Transport

The transport of substances across cell membranes from high concentration to low concentration without the use of energy.

Diffusion

A type of passive transport where small particles like oxygen and carbon dioxide move from areas of high concentration to low concentration.

Osmosis

The diffusion of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Facilitated Diffusion

A form of passive transport where particles move from high to low concentration through protein channels or 'doorways' without using energy.

Active Transport

The movement of particles against their natural tendency, from low concentration to high concentration, which requires energy ($ATP$).

Endocytosis

The process by which the cell membrane envelops and engulfs material too large to pass through the membrane, pinching off inside the cell.

Exocytosis

The process by which the cell membrane removes large material by surrounding it with a membrane and expelling it from the cell.

Mitosis

The process of cell division for growth and repair where one cell makes two cells, following the stages of Prophase, Metaphase, Anaphase, and Telophase (P-MAT).

Meiosis

The process where one cell makes four sex cells (sperm and eggs) to help in the reproduction of multi-cellular organisms.